This invention relates to catalysts for the conversion of higher hydrocarbons in general and more particularly to an improved catalyst giving increased activity and longer life.
In U.S. Pat. application Ser. No. 334,932, filed Feb. 22, 1973, now U.S. Pat. No. 3,878,130, granted Apr. 15, 1975, a catalyst for the conversion of higher hydrocarbons into a reformed gas mixture is disclosed. In particular, a catalyst for converting hydrocarbons into gas mixtures containing carbon monoxide, methane and/or hydrogen is disclosed. The catalyst is supported on an oxide catalyst carrier and includes oxides of the metals lanthanum, cobalt, nickel and uranium as the active components. The gas mixture obtained in the conversion of the hydrocarbons, which conversion is carried in the presence of a gas serving as an oxygen carrier such as air in what are referred to as reformed gas generators, i.e. the reformed gas, can be used to advantage as the fuel for an internal combustion engine, particularly the internal combustion engines used in motor vehicles. See also U.S. Patent Application Serial Nos. 318,616 (now U.S. Pat. No. 3,828,736); 283,412; 270,923 [now abandoned]; 372,422 [now U.S. Pat. No. 3,897,252] and 378,234, [now abandoned]. In an internal combustion engine the reformed gas burns along with secondary air in a faster and more complete manner than do the higher hydrocarbons themselves, e.g. hydrocarbons in the form of gasoline. By so converting the higher hydrocarbons into a reformed gas the emission of harmful substances in the exhaust gas can be considerably lower [see Siemens Forschungsund Entwicklungsberichte; vol. 2 (1973), no. 1, pages 58 to 62]. The aforementioned catalyst is inexpensive to manufacture and available on a large scale permitting its application at a low cost and without production difficulty in motor vehicles using reformed gas generators. This is in contrast to the use of platinum, for example, as a catalyst. It has also been discovered that the catalyst in general has increased activity and long life for converting mixtures of higher hydrocarbons and oxygen containing gases into a reformed gas. However, under certain operating conditions, particularly when the gas mixture to be converted is only in contact with the catalyst for a short time, difficulties may be encountered in the long run in converting large quantities of fuel and in generating reformed gas of uniformly high quality. It has been noted that, with short dwell times in the catalyst, minor losses in activity are more noticeable. In view of these difficulties, the need for an improved catalyst for the conversion of higher hydrocarbons which has a better life in activity, particularly when used in the manner in which the hydrocarbons do not dwell too long in the area of the catalyst, becomes evident.